The invention relates to wastewater treatment systems and in particular to wastewater treatment systems in which conversion of organic wastes and light energy to glucose takes place. Specifically, the invention relates to a complex system in which wastewater and other associated discharges are treated anaerobically and aerobically in a tank complex system where waste organics are reduced to inorganic forms available for algal culture in the uniquely designed rapid growth tanks.
This invention is an improved component of a pending application of the present invention for a Controlled Natural Purification System for Advanced Wastewater Treatment and Protein Conversion and Recovery, Ser. No. 95,969, filed Nov. 20, 1979.
In the operation of controlled natural purification systems for advanced waste water treatment and algae farming, the process operates through a complex series of tank means. In the last stage of the system various configurations of tanks are used. This last stage is referred to as the A-6 tank stage, particularly as provided in the referenced copending patent application.
Another descriptive term for these A-6 tanks in the controlled natural purification system is algae growth reactors, as they are involved in the last stage of algae growth, particularly when part of a system used in algae growth farming.
In the last stage of the process, various means are used to provide controlled liquid mixing and quiescence. The wind-powered impeller-mixer of this invention is an improved means to obtain that mixing and is so constructed so that when the impeller-mixer is not needed it can be stopped, such as during periods of culture-liquid quiescence, decanting operations, drawdown and recovery of primary algal concentration, and any similar such operations.
Normally such impeller-mixing operations may be operated by energy means provided from an external source, such as an electrical current to operate an electrical motor to turn the impeller. This invention provides an improved means for energy conservation by utilizing wind power.
The wind-powered impeller-mixer is a wind-driven rotor which drives a submerged impeller on a vertical shaft.
Coupled with this basic structure is a solenoid-operated clutch to engage and disengage the impeller.
Also coupled with the basic structure is a motor-generator and battery storage system. A generator to produce electrical energy for battery storage when the wind is blowing and turning the impeller-mixer and the motor, operated from the battery system, to drive the impeller-mixer, if needed, when there is little wind or when the wind is not blowing. A standby electrical connection to a separate electrical source, for emergency use, may be used in case of long periods of little or no wind, or in case of insufficient battery current at any time.
When the impeller-mixer is not needed, such as during periods of culture-liquid quiescence, decanting, drawdown and recovery of primary algal concentration, the impeller-mixer may be declutched so the wind-powered system may continue to charge the battery system.
When the impeller-mixer is in use during moderate to high wind velocities, the battery charging system can also be operated by means of the excess of wind-power available over and above that required for opening the impeller-mixer.
The impeller-mixer enhances algal growth by controlling the mixing to achieve a maximum number of algal cells in an optimum exposure to light and dark in accordance with hourly, daily, and seasonally changing conditions of solar insolation.
The impeller-mixers are set to impart a radial vector thrust to the culture liquid in relation to the normal peripheral circulation in the algae growth reactors. This radial vector thrust to the culture liquid along the bottom of the algae growth reactor gives a uniform mixing throughout each of the nodes of the algae growth reactor where a plurality of the impeller-mixers are installed.
It is to be understood that, although this invention is for a wind-powered impeller-mixer to mix a culture liquid in an algae growth reactor, this impeller-mixer may be used for other mixing purposes and that all such impeller-mixing uses are within the scope and intent of this invention.
It is, therefore, an object of the invention to provide an impeller-mixer that is wind-powered for energy conservation.
It is another object of the invention to provide a wind-powered impeller-mixer for use in mixing culture liquids in algae growth reactors.
It is also an object of the invention to provide a wind-powered impeller-mixer that can be declutched when mixing is not required.
It is still another object of the invention to provide a wind-powered impeller-mixer that additionally generates power for battery storage for use when wind is insufficient to operate the impeller-mixer.
It is yet another object of the invention to provide a wind-powered impeller-mixer that additionally is operable from battery storage power when wind is insufficient to operate the impeller-mixer.
It is yet still another object of the invention to provide a wind-powered impeller-mixer wherein the motor-generator and battery storage system is carried on the wind rotor means.
Further objects and advantages of the invention will become more apparent in the light of the following description of the preferred embodiments.